Apache County Sheriff's deputies advised residents east of Greer and south of Arizona 260 - the state highway that divides Eagar roughly in half - to get out. Authorities said the evacuation was not mandatory, but they were strongly recommending that people leave the area.

Arizona 260 was to remain open until the evacuations were complete.

Fire crews needed residents to leave so they could get trucks and other equipment into the area to protect as many structures as possible, according to William Bishop, a spokesman for the Eastern Arizona Incident Management Team.

Crews had been "up and down the road all day" setting a burn line, he said. Using bulldozers and other equipment, firefighters sought to create a barrier that would keep the wildfire from Eagar and Springerville, where hundreds of structures were at risk. Crews also removed brush from around homes.

Also evacuated was the community of South Fork. Residents of Springerville, which had been on a pre-evacuation alert, were waiting to see if they needed to follow suit.

Apache County incident-command officials urged residents evacuating Eagar to take U.S. 60 to Show Low. The Red Cross set up a shelter at the Blue Ride High School in Pinetop-Lakeside.

Those who needed help evacuating livestock or needed food or water for their animals were asked to call the Apache County Sheriff's Office at 928-337-4321 and dial 1. The Arizona Department of Agriculture was helping to make arrangements for livestock.

The blaze, already the second-largest in state history, is zero percent contained and threatens to consume more than the 389,000 acres already charred. At 486 square miles, the fire has burned an area nearly the size of Phoenix.

The manpower on the Wallow Fire has remained about the same for the past few days, with more than 2,100 people, 141 engines, 46 water tankers, eight bulldozers and 20 helicopters.

Eagar, about 18 miles west of the Arizona-New Mexico border, has a population of 4,516 residents Springerville is home to about 2,000 residents.

The Wallow Fire has grown so rapidly that management of the blaze will now be divided into three federal-incident teams.

"It's grown to the point that we need to branch it out," said Eric Nietzel, a spokesman with the Southwest Area Incident Management Type 1 team. "It's the complexity of the fire, and it's getting so big, we're going to zone it out, divide it into chunks."

Nietzel said that the original Type 1 Incident Commander, Joe Reinarz, will continue to oversee the Springerville and Eagar area of the fire along with his team.

A second Type 1 team will probably take command of the Reserve, N.M., area while another handles the White River or Horseshoe Lake area.

"It all depends on the geography of where the fire is headed," Nietzel said.

The three Type 1 teams will be managed by an Area Command to provide a single point of contact for the Forest Service, Nietzel said.

The raging fire could cut up to 40 percent of the power going to El Paso from the Palo Verde Nuclear Generating Station, which is west of Phoenix. If the lines are damaged, it could lead to rolling blackouts across El Paso, according to El Paso Electric. The utility started making adjustments to its system to reduce the adverse effects on costumers if the lines are damaged.

From 1990 to 2010, only eight fires in Arizona burned more than 50,000 acres, and only three of those burned more than 100,000 acres. In the 2011 fire season, three fires have already burned more than 50,000 acres, two of which have burned more than 100,000 acres.

The Horseshoe Two Fire has raged for nearly a month, burning more than 106,000 acres, injuring seven and costing more than $29.2 million to fight.

Nearly 900 personnel are combating the flames, with seven helicopters, 31 engines and three bulldozers assisting. Six structures were destroyed by the fire, and 65 other structures are in danger.

The evacuation order for the nearby community of Paradise has been lifted, but Whitetail and Chiricahua National Monument are still under evacuation orders.

While overshadowed by the much larger Wallow and Horseshoe Two fires, the Murphy Fire has burned more than 67,000 acres and is estimated to have cost $3 million since it began May 30. It's now merged with the smaller Pajarita Fire making it the the 11th-largest fire in Arizona history.

Fire officials said they were "holding (their) own" against the blaze Tuesday and were "very confident" the lines they'd set would hold.

Officials also said the pre-evacuation notice for Rio Rico had been lifted.

Frequently Asked Questions

Question: When did the fire begin and how?Answer: Fire officials believe an unattended campfire may have sparked the blaze about 1:30 p.m. May 29.

Q: Where does the name "Wallow Fire" come from?A: Fires are usually named after a feature near the start point. In this case, Bear Wallow Wilderness is located in the Apache-Sitgreaves National Forests, near where the fire was first reported.

Q: How many structures have been lost?A: Forest Service officials say ten structures have been lost to the fire.

Q: How many acres has the Wallow Fire burned?A: More than 311,000 acres as of Tuesday.

Q: How large is Wallow Fire compared to other fires across the country?A: The Wallow Fire is the largest active fire in the country, followed by the Honey Prairie Complex Fire in Georgia, which was sparked by lightning and has charred 166,297 acres. In addition, southern Arizona's Horseshoe Two Fire is the nation's third-largest at 104,000 acres.

Q: Historically, what are Arizona's largest wildfires?A: The largest fire in state history was the Rodeo-Chediski Fire, which charred more than 468,000 acres in eastern Arizona. The second-largest was the Cave Creek Complex Fire, which consumed more than 248,000 acres in 2005. The Wallow Fire is the third-largest in state history, followed by the 2004 Willow Fire at 119,000 acres and the still-burning Horseshoe Two Fire.

Q: What is a Type 1 Incident Management Team?A: A Type 1 team consists of highly trained and experienced wildfire personnel, from federal and state levels, specifically outfitted for wildland fires.

Q: What type of equipment is being used?A: As of Tuesday, 2,140 fire personnel were on the ground, utilizing 8 bulldozers, 141 fire engines, 46 water tenders and 20 helicopters.

Q: What types of helicopters are being used?A: There are three types of helicopters. The Type 1 is the heavy-lift helicopter sometimes called a sky crane. It has the ability to dump up to 2,000 gallons of water. Medium-sized helicopters can dump about 500 gallons. Light helicopters are used to move supplies and keep an eye on the fire.

Q: What magnitude is the current evacuation?A: Fire officials said the following communities have been evacuated: Sunrise, Greer, Blue River, Alpine, Nutrioso, Hannagan Meadow Lodge, Sprucedale Guest Ranch, Brentwood Church Camp, Hannagan campground, KP campground, West Fork Black River campground, East Fork Black River campground, Escudilla Mountain Estates, Bonita, White Mtn. Acres, Dog Patch and the H-V Ranch. The towns of Eager, Springerville and South Fork are on pre-evacuation notice.